Testicular development, sex hormones and boar taint in pig lines divergent for residual feed intake

Armelle Prunier (1) , Yvon Billon (2) , Julien Ruesche (3) , Stéphane Ferchaud (2) , Hélène Gilbert (3)

1 PEGASE - Physiologie, Environnement et Génétique pour l'Animal et les Systèmes d'Elevage [Rennes]
2 GenESI - Génétique, Expérimentation et Système Innovants
3 GenPhySE - Génétique Physiologie et Systèmes d'Elevage

Improving feed efficiency and rearing entire male pigs are relevant strategies to reduce feed cost and environmental waste in pig production. The major constraint for rearing entire male pigs being boar taint, an experiment was performed to determine the consequences of a divergent selection on residual feed intake (RFI: low RFI = LRFI; high RFI = HRFI) on pubertal development and boar taint. Purebred French Large White male pigs from two divergent lines for RFI (9th generation of selection, n = 45 or 43 pigs/line from 33 litters) were reared in two batches (n = 19 to 24 pigs/line/batch). Blood samples were drawn at 15 and 166±1 days of age (mean±SD) and pigs were weighed. After slaughter at 167±1 days of age, a backfat sample was collected in the neck and the genital tract was removed for testis and epididymis weighing after tissue trimming. Percentages of testis and epididymis weight relatively to liveweight were calculated for statistical analyses. All data were analyzed by ANOVA using R, including line and batch as fixed effects and litter as a random effect. When necessary, a log transformation was applied before analysis and adjusted means were backcalculated. Before slaughter, LRFI pigs were lighter than HRFI pigs (100±2 vs 106±2 kg liveweight, P<0.02). Plasma testosterone at both ages and plasma oestradiol-17 at 15 days were similar in both lines (P>0.1). However, plasma oestradiol-17 before slaughter (9.0 vs 17.5 pg/ml), fat androstenone (0.22 vs 0.34 µg/g pure fat), testis (3.5 vs 4.4‰) and epidydimis (1.18 vs 1.62‰) relative weights were lower in HRFI than LRFI pigs (P<0.001). Fat skatole was lower in HRFI than in LRFI (0.10 vs 0.28 µg/g pure fat, P<0.001) in the first batch with slaughter performed on the 17th July 2016 during a summer heat wave. Fat skatole was low in both lines (0.08 µg/g) in the second batch with slaughter performed on the 29th August 2016. Overall, these data indicate a lower testicular activity in the HRFI than in the LRFI line, which suggests the existence of genetic links between feed efficiency and reproduction

Mots clés: boar taint; feed efficiency; puberty; steroid

Mots clés: puberte; efficience alimentaire; stéroïde; lignée divergente; porc mâle entier; consommation alimentaire résiduelle

Domaines: Sciences du Vivant [q-bio]

Armelle Prunier, Yvon Billon, Julien Ruesche, Stéphane Ferchaud, Hélène Gilbert. Testicular development, sex hormones and boar taint in pig lines divergent for residual feed intake. 69. Annual Meeting of the European Federation of Animal Science (EAAP), Aug 2018, Dubrovnik, Croatia. Wageningen Academic Publishers, Annual Meeting of the European Association for Animal Production, 24, 2018, Annual Meeting of the European Association for Animal Production. ⟨hal-01870579⟩